On the contrary, Japanese Patent Application Laid-Open (JP-A) No. Hei7 (1995)-244801 (Patent Document 1) discloses a spin heating recording method in which a high frequency magnetic field satisfying a magnetic resonance condition is supplied to a magnetic recording medium by following a high frequency source provided at the outside by a motion of the magnetic head and a spin of the magnetic recording medium absorbs energy of the high frequency magnetic field, and as a result, writing may be performed even on a coercive magnetic recording medium in a low magnetic field without actually increasing a temperature of the magnetic recording medium by using coercive force which effectively deteriorates.
Recently, X. Zhu and J-G. Zhu, “Bias-Field-Free Microwave Oscillator Driven by Perpendicularly Polarized Spin Current” IEEE Trans. Magn., vol. 42, pp. 2670-2672, 2006 (Non-Patent Document 2) discloses a spin torque high frequency oscillator (STO) which has a practical minute structure using a high frequency field generation layer (FGL) generating a high frequency magnetic field by high-speed rotation by spin torque. J-G. Zhu, X. Zhu, and Y. Tang, “Microwave Assisted Magnetic Recording”, IEEE Trans. Magn., Vol. 44, no. 1, PP125-131 (2008) (Non-Patent Document 3) discloses a microwave assisted magnetic recording (MAMR) scheme in which the spin torque oscillator (STO) having the same structure is adjacent to a main magnetic pole of the vertical magnetic head and a switching magnetic field is decreased by exciting precession of medium magnetization in a high frequency magnetic field in a microwave band from the STO, and information is magnetically recorded on a magnetic recording medium having large magnetic anisotropy to thereby achieve high density.
Further, S. Batra and W. Scholz, “Role of Media Parameters in Switching Granular Perpendicular Media Using Microwave Assisted Magnetic Recording”, IEEE Trans. Magn., Vol. 45, PP889-892 (2009) (Non-Patent Document 4) and S. Batra and W. Scholz, “Micromagnetic modeling of ferromagnetic resonance assisted Switching”, J. App. Phys., 103, 07F539 (2008) (Non-Patent Document 5) disclose a relationship between various design conditions of the microwave assisted magnetic recording scheme and effects thereof. By the Non-Patent Documents 4 and 5, recently, research and development for commercialization of the microwave assisted magnetic recording scheme have been rapidly accelerated.
Meanwhile, as a commercialized scheme in advance as a method of increasing recording density of the vertical magnetic recording, a multilayered medium such as an exchange coupled composite (ECC) medium and a CAP medium is included. For example, the multilayered medium is disclosed in R. H. Victora and X. Shen, “Composite Media for Perpendicular Magnetic Recording”, IEEE. Trans. Magn. vol. 41, PP. 537-542 (2005) (Non-Patent Document 6). Further, with respect to a multilayered medium for obtaining a different effect from the ECC effect disclosed in the Non-Patent Document 6, for example, the multilayered medium in which a high Ku layer is provided on a surface of the recording film or a ground interface in order to suppress noise due to a reverse magnetic domain generated from a low Ku area where the surface of the recording film or the ground interface is local is disclosed in Japanese Patent Application Laid-Open (JP-A) No. Hei11(1999)-296833 (Patent Document 2) and Japanese Patent Application Laid-Open (JP-A) No. 2000-113442 (Patent Document 3).